Safety arrangement for engine operated accessory



Sept. 27, 1966 w. J. BARTO 3,275,177

SAFETY ARRANGEMENT FOR ENGINE OPERATED ACCESSORY Filed Jan. 15, 1964 2 Sheets-Sheet 1 INVENTOR.

1/7/1717 vKY/ F/l/Afik a "a v 1 7 E 72) 0mm Guns W. J. BARTO Sept. 27, 1966 SAFETY ARRANGEMENT FOR ENGINE OPERATED ACCESSORY Filed Jan. 15, 1964 2 Sheets-Sheet 2.

INVENTOR. Mum/*1 5497? BY 7% ArTUP/YEY 70 0/715 Cu s United States Patent 3,275,177 SAFETY ARRANGEMENT FOR ENGINE OPERATED ACCESSORY William J. Barto, Philadelphia, Pa., assignor to Eaton Yale & Towne Inc., a corporation of Ohio Filed Jan. 15, 1964, Ser. No. 337,771 8 Claims. (Cl. 214-650) This application is a continuation-in-part of my application Serial No. 261,422, filed February 27, 1963, now abandoned.

This invention relates to the use of an internal combustion engine for operating accessories on a lift truck or the like.

Internal combustion engines are sometimes used for operating various accessories on a lift truck. For example, in my co-pending application, Serial No. 238,451, filed November 19, 1962, now Patent No. 3,187,989, there is disclosed a system whereby vacuum for operating a vacuum cup load gripping attachment is created by operation of an internal combustion engine.

In arrangements of this type, if the internal combustion engine should stall, the accessories will, of course, stop operating. While in many applications this may not be important from the viewpoint of safety, for other applications such as where the accessory is a load handling device, a sudden failure of the accessory to operate because of stalling of the engine, may create a very dangerous situation.

The purpose of this invention is to provide a simple, inexpensive safety arrangement which will insure continued operation of the accessory for sufiicient time to allow alleviation of the dangerous situation in the event of failure of the internal combustion engine to be selfoperating.

To this end, the safety arrangement of the invention includes auxiliary means which are automatically actuated to drive the engine if the engine should fail to be self-operating. By this arrangement, the engine will either be restarted, or will be driven by the auxiliary means to continue operation of the accessory for a sufficient time to allow alleviation of the dangerous situation.

As a feature of the invention, the engine includes a battery operated electric starter motor, and the starter motor is utilized as the auxiliary means to drive the engine in the event the engine should fail to operate. Operation of the starter motor to drive the engine is initiated by control means responsive to a predetermined decrease in the speed of the engine. By this arrangement, the starter motor may be utilized in the usual manner to start the engine, and at the same time, be used for emergency driving of the engine in the event the engine fails to be self-operating. Thus, the starter motor acting through the engine continues operation of the accessory without the necessity of special clutches or controls for connecting the starter motor to the accessory.

Other objects and advantages of the engine will become apparent from the following description when read in conjunction with the accompanying drawings in which:

FIG. 1 is a schematic view of a vacuum system incorporating a safety arrangement in accordance with the invention, with vacuum being created by the large flow of air through the air intake of an internal combustion engine during operation of the engine, and

FIG. 2 is a schematic view of a vacuum system incorporating a safety arrangement in accordance with the invention, with the vacuum being created by a separate vacuum pump which is driven by the internal combustion engine.

Referring to the drawings, and in particular to FIG. 1, a safety arrangement in accordance with the invention is "ice shown applied to a vacuum system of the type shown in my co-pending application Serial No. 238,451, filed November 19, 1962.

The vacuum system includes an internal combustion engine 10 having a carburetor 11. The carburetor 11 is adjusted so that the engine 10 will operate efliciently at a substantially constant speed at a sub-atmospheric air pressure, e.g. 16" of Hg, and the large flow of air through the air intake 12 of the carburetor 11 to support combustion within the engine is utilized to create vacuum or suction for operating a vacuum device.

In the particular system illustrated, the vacuum device is a vacuum cup gripper incorporating a plurality of vacuum cups, one of which is shown at 13 in the drawing in gripping relationship to a load L. Each vacuum cup 13 is connected to a manifold 14 by a conduit 15 and a sensing valve 16. The sensing valve 16 is actuated to connect the cup 13 to the manifold 14 by movement of a sensing lever 17 as the cup 13 is moved against the surface of the load.

The manifold 14 is connected through a solenoid operated valve 18, a metering valve 19, and a conduit 20 to the air intake 12 of the carburetor 11, so that the flow of air to the engine through the air intake 12, during operation of the engine, creates suction or vacuum at the cups 13. -If it is desired to release the vacuum from the cups to release the load, the solenoid operated valve 18 is actuated to connected the manifold 14, and therefore the cups 13, with atmospheric air.

The metering valve 19 prevents excessive 'flow of air to the carburetor and choking of the engine in the event that the vacuum cups 1 3 are not completely covered by the load or are in engagement with a porous load. A pressure actuated bypass valve 21, which is connected to the conduit 20, admits air at atmospheric pressure to the air intake 12 of the carburetor 11 as necessary to prevent stalling of the engine by air starvation in the event that all the vacuum cups are covered by the surface of a non-porous load or the sensing valves 16 are closed. The metering valve 19 and the bypass valve 21 therefore serve to maintain the air pressure within the conduit 20 substantially at the sub-atmospheric pressure to which the carburetor 11 is adjusted, to thereby prevent stalling of the engine 10 either by choking or air starvation.

With the vacuum system as described, it will be appreciated that if the engine 10 should stall, the vacuum on the vacuum cups 13 would be lost with resulting dropping of the load L.

In accordance with the invention, such sudden loss of vacuum is prevented by auxiliary means which are automatically actuated to drive the engine 10 if the engine fails to be self-operating, so that the engine continues to function as a pump to maintain the vacuum or suction.

In the particular form of the invention disclosed, the auxiliary means consist of an electric starter motor 22 which is connected to the crank shaft 23 of the engine by a belt drive 24, and which is adapted to be operated from a battery 25. As will be described hereinafter, the starter motor 22 is used both to initially start the engine 16 and to drive the engine in the event that the engine should fail to be self-operating.

Three control switches, generally indicated at 26, 27 and 23, are shown in the drawing for starting operation of the starter motor 22 to drive the engine 10 in the event the engine 10 should fail to be self-operating. In the drawing, the switches are shown in the open position, which is the position they occupy when the engine 10 is operating normally to provide vacuum to the cups 13. As will be described, each of these control switches is responsive, either directly or indirectly, to a decrease in the speed of the engine 10 to start operation of the starter motor 22 to drive the engine and any one of the three switches may be used alone without the other switches. However, the use of all three switches does provide a greater margin of safety.

When all three switches are used, they are connected in parallel with each other and in series with a starter switch 29, as shown in the drawing. When the engine 10 is not operating, each of the switches 26, 27 and 28 is closed, so that closing of the starter switch 29 completes a circuit between the starter motor 22 and the battery to energize the starter motor 22 to start operation of the engine 10. The starter switch 29 remains closed during operation of the engine 10. After the engine starts, starter motor 22 is disconnected from the battery 25 by opening of the switches 26, 27 and 28.

The control switch 26 is a pressure actuated switch having a diaphragm 30, and a plunger 31 which is urged by a spring 32 in a direction to hold contacts 33 closed. When the engine 14) is operating properly, so that a vacuum is created in the conduit 20, the pressure differential on the diaphragm 30 causes the plunger 31 to move inwardly against the force of the spring 32 to open the contacts 33, thereby disconnecting the starter motor 22 from the battery. If, however, there is a predetermined increase in the pressure in the conduit 20, thereby indicating a predetermined decrease in the speed of the engine 10, the plunger 31 is moved by the compression spring 32 to close the contacts 33. The closing of contacts 33 completes a circuit through previously closed starter switch 29 to connect the battery 25 to the starter motor to start operation of the starter motor to drive the engine 10, so that the engine 10 continues to function as a pump to maintain the vacuum.

The control switch 27 is also a pressure actuated switch, but is connected to the oil line 34 of the engine 10. The switch 27 includes a plunger 35, mounted on a diaphragm 36, which is urged by a spring 37 in a direction to hold contacts 38 closed. When the engine 10 is operating properly at the predetermined speed, the oil pressure in the oil line 34 increases, forcing the plunger 35 outwardly against the force of the spring 37 to open the contacts 38 so that the starter motor 22 is disconnected from the battery 25. If, however, the oil pressure in the oil line 34 should decrease in the speed of the engine 10, the plunger 35 is moved by the spring 37 in a direction to close the contacts 38 to complete a circuit through the closed starter switch 29 to connect the battery 25 to the starter motor 22 to drive the engine '10.

The control switch 28 is a centrifugally operated switch which is operated off the drive shaft 23. The switch ineludes contacts 39 which are normally urged to a closed position by spring 40. When the engine is operating normally and reaches the predetermined speed, a control plate 41 is drawn downwardly by outward movement of fly balls 42 which are mounted through spring arms 42a on a shaft 43 which is driven from the crank shaft 23 through bevel gears 44. This downward movement of the control plate 41 opens the contacts 39 to thereby disconnect the starter motor 22 from the battery 25. If the speed of the engine 10 decreases a predetermined amount, the control plate 41 again moves upwardly allowing the contacts 39 to be again closed by the spring to complete a circuit through the closed starter switch 29 to connect the battery 25 to the starter motor 22 to start operation of the starter motor to drive the engine 10, so that the engine continues to function as a pump.

Thus either of the control switches 26, 27 or 28 serve to start operation of the starter motor 22 to drive the engine 10 so that the engine It) continues to function as a pump it the engine 10 should fail to be self-operating. Thus the danger of losing the vacuum on the cups 13 due to stalling of the engine is effectively prevented.

Referring now to FIG. 2, the safety arrangement of the invention is shown applied to a slightly different form of v cuum y tem fIOm that shown in FIG. 1.

In FIG. 2, vacuum or suction is obtained by a vacuum or suction pump 45 which is driven by a belt 46 from a pulley 47 which is connected to the drive shaft 33 of the internal combustion engine 10. The line 20 is connected to the suction side of the vacuum pump 45, instead of to the intake 13 of the carburetor 11 as in the arrangement of FIG. 2, whereby the pump 45 provides the vacuum or suction for operating the vacuum cups 13. In this form of vacuum system, the valve 21, as previously described in connection with the vacuum system in FIG. 1, may be connected to the vacuum line 20 so that it opens when the vacuum increases above a predetermined value, to therefore prevent overloading of the engine 10 and overheating of the vacuum pump 45.

The safety arrangement as shown in FIG. 2 functions in the same manner as described in conjunction with FIG. 1 to start operation of the starter motor 22 to drive the engine It if the engine should fail to be self-operating, to thereby continue operation of the vacuum pump 45.

While certain forms of the invention have been shown and described, it will be appreciated that this is for the purpose of explanation and illustration, and that changes and modifications may be made therein without departing from the spirit and scope of the invention.

I now claim:

1. In a lift truck having a load gripping device that requires for its safe operation the application of a degree of power to said device, an internal combustion engine normally operating for supplying power to said device, a motor effective when energized to drive said internal combustion engine at a speed that will supply said degree of power, and control means responsive to a decrease in the speed at which the engine operates whereby to energize said motor, so that the engine may effect safe operation of said load gripping device when said engine fails to operate normally.

2. A construction as set forth in claim 1, in which said motor is an electric motor for starting the operation of said internal combustion engine, there being a power circuit connected to said motor, a starter switch in said power circuit, and said control means including a switch connected in series with the starter switch in said circuit so as to control said motor for developing the degree of power necessary to safe operation of the load gripping device while said starter switch is in a circuit closing position.

3. In a lift truck having a load gripping vacuum device that requires for its safe operation the application of a degree of vacuum to said device, a normally operating internal combustion engine, means whereby said engine supplies vacuum for operating said device, a motor effective when energized to drive said internal combustion engine at a speed that will maintain said degree of vacuum, and means responsive to a decrease in the speed at which the engine operates whereby to energize said motor, so that the engine may effect safe operation of the load gripping vacuum device when said engine fails to operate normally.

4. A construction as set forth in claim 3, in which there is a pressure actuated bypass valve that is connected to the means whereby the engine supplies vacuum and that will admit air to those means when the vacuum reaches a relatively high degree, so that there will be no excessively high vacuum that might act by decreasing the engine speed to cause the motor to be energized.

5. In combination, a load gripping device that requires for its safe operation the availability of a degree of power, an internal combustion engine normally operating at a speed to develop said degree of power, means for applying power developed by said engine to the load gripping device, a motor for driving said internal combustion engine, a source of energy effective when applied to said motor to operate said engine at a speed developing said degree of power, and control means responsive to the speed of the internal combustion engine and iacting'when said engine operates at a speed less than its normal operating speed to apply the energy from said source to said motor, so that safe operation of the load gripping device may continue when the engine fails to operate normally.

6. In combination, a load gripping vacuum device that requires for its safe operation a degree of vacuum that is continuously available, an internal combustion engine, means whereby said engine when operating at a normal speed develops said degree of vacuum for operating said vacuum device, a motor effective when energized to drive said engine, and control means responsive to the speed of the internal combustion engine and acting to energize said motor when the speed of said engine decreases from said normal speed, so that the motor will cause said engine continuously to develop the degree of vacuum that is necessary for the safe operation of said load gripping vacuum device.

7. A combination as set forth in claim 6, in which said motor is an electric motor for starting the operation of said internal combustion engine, there being a power circuit connected to said motor, a starter switch in said circuit, and said control means including a switch connected in series with the starter switch in said circuit and eflFective while the starter switch is in circuit closing position to control the operation of the internal combustion engine by said motor for developing the degree of vacuum necessary to safe operation of the vacuum device.

8. A combination as set forth in claim 6, in which there is a pressure actuated bypass valve that is connected to the means whereby the internal combustion engine develops vacuumand that will admit air to those means when the vacuum rises to a relatively high degree, so that there will be no excessively high vacuum that might cause the motor to be energized due to a decrease in engine speed.

References Cited by the Examiner UNITED STATES PATENTS 1,235,423 7/1917 Boyett 123-179 1,533,104 4/1925 Davis 123-179 2,147,019 2/1939 Ericson 123-179 2,363,534 11/1944 Lachapelle 123-l79 2,401,426 6/1946 Killoran 230-13 2,685,650 8/1954 Collins 123-179 2,725,864 12/1955 Coffey 123-179 2,741,186 4/1956 Nallinger 12 3-179 2,757,295 7/1956 Briggs 123179 2,763,746 9/1956 Keeven 123179 LAURENCE V. EFNER, Primary Examiner. 

1. IN A LIFT TRUCK HAVING A LOAD GRIPPING DEVICE THAT REQUIRES FOR ITS SAFE OPERATION THE APPLICATION OF A DEGREE OF POWER TO SAID DEVICE, AN INTERNAL COMBUSTION ENGING NORMALLY OPERATING FOR SUPPLYING POWER TO SAID DEVICE, A MOTOR EFFECTIVE WHEN ENERGIZED TO DRIVE SAID INTERNAL COMBUSTION ENGINE AT A SPEED THAT WILL SUPPLY SAID DEGREE OF POWER, AND CONTROL MEANS RESPONSIVE TO A DE- 